What is VCO tuning constant | VCO tuning methods

VCO is an oscillator whose frequency can be varied by voltage or current.
VCO has tuning constant designated often as KVCO which is specified in Hz/Volt
or Hz/Ampere. This constant is also known as VCO gain.

The figure depicts the same VCO tuning constant.
For example if tuning range is 2.4 GHz to 2.483 GHz as per bluetooth standard and
if tuning voltage range is 2.7 Volt.
➨For this case, tuning constant is equal to { ((2.483-2.4)x103)/2.7 }= 30.7 MHz/Volt.

The phrase tuning constant is deceptive as it becomes larger when tuning range is increased and
so on.